It is known that only one of the optical isomers constituting a racemic modification has a physiological activity in the natural world. It has recently been found in the field of drugs that only one of the optical isomers constituting a racemic modification has a remarkable pharmacological effect or a low toxicity in some cases, for which the development of a drug with an isolated optical isomer has risen in importance.
Only a few methods for the separation of optical isomers can be practically conducted on an industrial scale, though many methods therefor have been known hitheroto. Therefore, a method which can separate optical isomers easily and at a low cost has been sought. In recent years, with the progress in high-performance liquid chromatography, methods for separating optical isomers have become known generally and separatory columns having various performances have also been reported.
However, there are only a few columns usable for the separation of optical isomers while it is known that very many compounds have optical isomers. In addition, not all optical isomers can always be efficiently separated, and therefore the development of a new separatory column has been expected.